1. Field of the Invention
Generally, the present disclosure generally relates to the manufacturing of sophisticated semiconductor devices, and, more specifically, to a metal e-fuse device that employs an intermetallic compound programming mechanism and various methods of making such an e-fuse device.
2. Description of the Related Art
With continued scaling in semiconductor technologies to increasingly smaller geometries, on-chip e-fuse implementations provide an attractive alternative to conventional fusing schemes for integrated circuits. In terms of area efficiency and performance impact, e-fuse technology presents a significant improvement over fuse technologies with optical based programming. Programmable devices for integrated circuits require a dependable methodology for customizing a device in a repeatable and reliable manner. Fusing of programmable connections in microprocessors, FPGAs and other VLSI designs is a common technique to achieve the flexibility of programmability. Common applications for e-fuse technology include memory array redundancy, package identification coding and post-manufacture programming of logical functions. Since each e-fuse is a single primitive device, additional logic and circuitry are necessary to facilitate programming and sensing.
A typical e-fuse device fabricated in silicon-based integrated circuits is typically programmed using a large voltage, relative to the operating voltage of the integrated circuit, to melt and separate the fuse body material. This process changes the fuse material from a low resistance to a high resistance, which may be measured by “sensing” circuitry to determine whether or not the e-fuse has been programmed. As process technology for integrated circuits has progressed, maximum operating voltages have scaled commensurately downward with physical geometry, making it difficult to provide sufficient voltage to program the e-fuse without damaging logic circuitry associated with the fuse bank. In addition, the current density requirements for metal interconnect layers used to supply e-fuse programming currents are typically much greater than for signal interconnect lines. As such, fuse programming buses must be implemented with wide metal wires that consume a disproportionate amount of interconnect resources.
Furthermore, some e-fuse devices may require multiple programming pulses to ensure adequate resistance levels for the e-fuse device, thereby increasing programming and test time cycles. However, repeated programming may also lead to an unfused condition in the programmed fuse if a sufficiently high voltage is applied. In that instance, the heating associated with re-programming may cause the fuse material to rejoin, thereby further degrading fuse-related yield.
The present disclosure is directed to a novel e-fuse device, and various methods of making such a device that may solve or at least reduce one or more of the problems set forth above.